A Simple Synthesis of 1, 3-Dialkylpyrido [2, 3-d] pyrimidines

Abstract

A new and convenient synthesis of 1, 3-dialkylpyrido [2, 3-d] pyrimidine-2, 4 (1H, 3H)-diones from 6-allylamino-and 6-(substituted allyl) aminouracils by PdCl₂-CuCl-O₂-catalyzed oxidative cyclization is described. Further, 1, 3-dimethylpyrido [2, 3-d] pyrimidine 2, 4 (1H, 3H)-dione (4a) was prepared by the reaction of 6-allylamino-1, 3-dimethyluracils (3a) with (AcO)₂ Pd and by the thermal cyclization of 3a.